What is Heart Failure?

Heart failure is the inability of the heart to fill with or pump out enough blood to meet the body’s needs. Heart failure doesn’t mean that your heart has stopped or is about to stop working, just that it has become an inefficient pump.

Heart failure is not one single disease, but rather a group of signs and symptoms caused by many different disease processes that have weakened the heart over time and left it unable to pump blood efficiently. Heart failure can take different forms in different people. For some, heart failure may involve a blood-pumping problem (systolic heart failure); for others, it may be a blood-filling problem (diastolic heart failure). Heart failure may affect only one side of the heart—the left or the right—or both sides at the same time. See our section on the different forms of heart failure for more information on left-sided and right-sided heart failure.

Heart failure is sometimes referred to as congestive heart failure, but this is misleading because the buildup of fluid (congestion) in the lungs and other parts of the body doesn’t occur in everyone. Heart failure is also called chronic heart failure because the condition usually develops gradually over a long period of time.

What are the symptoms of heart failure?

The most common symptoms of heart failure are shortness of breath while active or lying down, fatigue, persistent coughing, and swelling of the ankles, feet, legs and sometimes the belly.Fatigue is the most common sign of heart failure in elderly people, which may be why it often takes a long time for them to be diagnosed. The symptoms are generally the same whether you have systolic heart failure or diastolic heart failure. Women are more likely than men to have shortness of breath (67% to 63%) and swollen ankles (29% to 22%). Symptoms can be mild to severe, and they can come on suddenly or begin gradually and worsen over time. Mild symptoms, such as shortness of breath with activity, are often mistaken for signs of aging. For this reason, many women are unaware of their condition until years after their heart begins to deteriorate. Some people in the early stages of heart failure don’t even have any symptoms.

The symptoms of heart failure are common in other conditions, such as asthma and lung disease. If you have symptoms such as shortness of breath and persistent cough, your doctor will do a thorough medical history and physical examination and order blood and imaging tests to rule out other possible causes for these symptoms and to check on your heart’s pumping capacity.

See our section on the signs and symptoms of heart failure for more detailed information.

What happens to the heart during heart failure?

Conditions that can lead to heart failure, such as high blood pressure and coronary artery disease, share the common feature of making the heart work harder to pump blood to the body. To make up for the added strain, the heart compensates by changing its shape in different ways. The pumping chambers (the ventricles) can stretch (dilate) to hold more blood for pumping. The chambers can also develop a thicker muscle wall (hypertrophy) that allows them to pump blood with more force, increasing the amount of blood pumped to the body.

These “compensatory” changes can go on for many years without impairing the heart’s ability to function. This is why you may not have any symptoms when your heart first begins to fail, because the heart is compensating for its gradual decline in performance. Eventually, however, the heart can no longer compensate and begins to weaken. In those who develop an enlarged (dilated) heart, the walls of the heart become over-stretched and too weak to pump blood efficiently anymore. In the case of hearts with thickened (hypertrophied) muscle, the walls become too thick and stiff to relax and allow the heart to fill with enough blood, resulting in less blood available for pumping. No matter what the cause (dilated or hypertrophied hearts), blood begins to back up and build up in the lungs, arms, legs, and ankles. At this stage of heart failure, you notice symptoms such as shortness of breath, fatigue, and swelling. From here on, the disease can progress and the symptoms worsen, but they may stabilize and improve with the proper treatment.

How common is heart failure?

Approximately 5 million Americans are currently living with heart failure, half of them women. In 2004, heart failure contributed to approximately 285,000 deaths; close to 60% were women. From age 40, the average woman or man has a 1 in 5 (20%) chance of developing heart failure at some point in their life. African-American women have a 50% to 60% higher risk than women of other races.

Heart failure can happen to anyone. Until age 80, heart failure is more common in men than in women. After age 80, heart failure begins to occur more frequently in women than in men, largely because more women than men live beyond the age of 80.

Heart Failure – Stages & Classification

What are the different stages of heart failure?

The course of heart failure varies from person to person and depends on individual factors, including the cause of heart failure and the severity of symptoms. For many people, heart failure is a long-term, progressive deterioration of the heart’s pumping ability that starts slowly and gets worse over time. When symptoms start, you may feel tired and short of breath after performing tasks that you used to do with ease. As heart failure progresses, the symptoms can get worse. For other people, heart function may improve with current treatments, and they can recover fully or have long periods of stability.

The American Heart Association (AHA)/American College of Cardiology (ACC) staging system for heart failure focuses on the progression and worsening of the condition over time. The AHA/ACC staging system moves forward—from one stage to the next—based on the progression of the disease. It helps doctors identify people who are at high risk for heart failure but don’t have the condition yet ( Stage A), those with heart damage but no symptoms of heart failure ( Stage B), and those with heart damage and with symptoms of heart failure (Stages C and D). The AHA/ACC staging system helps doctors prevent heart failure in those at risk and complements the New York Heart Association (NYHA) classification system, which gauges the severity of symptoms in people who are at stages C and D of the AHA/ACC system.

AHA/ACC Heart Failure Stages

Stage

Description

A

People at high risk for developing heart failure but who do not have heart failure or damage to the heart

B

People with damage to the heart but who have never had symptoms of heart failure; for example, those who have had heart attack

C

People with heart failure symptoms caused by damage to the heart, including shortness of breath, tiredness, inability to exercise

D

People who have advanced heart failure and severe symptoms difficult to manage with standard treatment

The New York Heart Association (NYHA) Classification System

The NYHA classification system is used to classify symptoms of heart disease, including heart failure. Symptoms are graded based on how much they limit your functional capacity (your ability to perform basic physical tasks). Unlike the AHA/ACC staging system, the NYHA class often can shift from one level to another; for example, if you respond well to treatment and your symptoms improve, your NYHA class can go down. If you don’t respond well and your symptoms continue to worsen, your NYHA class can go up.

Marked or noticeable limitations of physical activity – comfortable at rest, but less than ordinary physical activity causes tiredness, heart palpitations, or shortness of breath

4 (Severe)

Severe limitation of physical activity – unable to carry out any physical activity without discomfort. Symptoms also present at rest. If any physical activity is undertaken, discomfort increases.

Heart Failure – Causes and Who is at Risk

What causes heart failure?

Heart failure can be caused by any disease or condition that damages the heart muscle directly or makes the heart work harder to pump out blood. The heart muscle may stretch too much and become too weak to pump efficiently, or it may thicken too much and become too stiff to relax and fill with enough blood. A wide range of conditions can damage the heart muscle, from long-term wear and tear on the heart to alcohol abuse and viral infections. Most cases of heart failure can be attributed to one or more of the following conditions.

High lood Pressure

High blood pressure is a leading cause of heart failure in women, especially in African-American women. High blood pressure forces the heart to work harder to pump out blood against the increased pressure in the blood vessels. Over time, the increased workload can damage the heart muscle, causing it to become weak or stiff. Women with high blood pressure have 3 times the risk of developing heart failure compared to women without high blood pressure. Women with heart failure are more likely than men to have high blood pressure. The Framingham Heart Study found that high blood pressure accounted for nearly 60% of heart failure cases in women, compared with about 40% in men.

Coronary Artery Disease

Coronary artery disease (CAD) is a major cause of heart failure in women. When the coronary arteries along the surface of the heart become blocked or narrowed with plaque, the heart doesn’t receive enough blood and oxygen, eventually causing the muscle to weaken. Heart attacks caused by blocked arteries can destroy heart muscle and put you at high risk for developing heart failure. Although CAD and heart attacks are a less common cause of heart failure in women than in men, women who do suffer a heart attack have a higher risk than men of developing heart failure within 5 years: 37% of women compared with 29% of men.

Diabetes

Diabetes is a significant cause of heart failure, increasing the risk of developing heart failure 5-fold in women—almost twice the risk increase seen in diabetic men. Diabetes itself can directly damage the heart muscle, or it can accelerate the development of high blood pressure, CAD, and heart attacks, all of which can damage the heart.

Obesity

Obesity directly increases your risk of developing heart failure by making your heart work harder to supply blood because of the extra weight. Obesity also contributes to other heart failure-related conditions such as high blood pressure and diabetes. Women with heart failure are more likely than men to be obese. The Framingham Heart Study found that each 1-point increase in body mass index (BMI) was associated with a 7% increase in the risk of heart failure in women and a 5% increase in men.

Heart Muscle Disease (Cardiomyopathy)

Heart failure can also develop as a result of heart muscle disease (cardiomyopathy) that causes the muscle of the pumping chambers to enlarge by stretching or thickening, damaging the heart’s ability to pump blood efficiently to the rest of the body. Heart muscle disease can be caused by viral infections (such as viruses causing a common cold), using substances toxic to the heart (for example, alcohol and illegal drugs such as cocaine), or certain chemotherapy drugs. Some cases of heart muscle disease are caused by an inherited genetic defect; in many others, the cause is unknown.

Although rare, one cause of heart failure unique to women is peripartum cardiomyopathy: a weakening of the heart muscle developing in the last 3 months of pregnancy or in the first 5 months after delivery. Most cases occur in women older than 30, especially in African-American women. Although it is not known what causes this condition, risk factors include multiple pregnancies, multiple births (for example, twins), high blood pressure developed during pregnancy, and preeclampsia during pregnancy.

Other Causes

Other causes of heart failure include heart valve disease, irregular heartbeats or arrhythmias (such as atrial fibrillation), or heart defects present at birth (congenital heart disease), all of which cause the heart to work harder to pump blood.

Who is at risk for heart failure?

Risk Factors You Can’t Change

Age: Although heart failure can happen at any age, aging increases the risk dramatically because as we age and our muscles weaken, so does our heart. About 70% of women with heart failure are over the age of 50, and heart failure is the number one reason for hospital visits for people who are 65 years or older.

Gender: Although men have a higher risk than women of developing heart failure, more women have the condition in actual numbers because more women than men live into their 70s and 80s, when heart failure is most common. The underlying causes of heart failure vary between women and men. Coronary artery disease (CAD) is a less widespread cause of heart failure in women than it is in men, while women with heart failure are more likely than men to have high blood pressure.7When a woman develops CAD, however, she is much more likely to develop heart failure than if she had high blood pressure, a more widespread disease.

Race: African-American women are more likely to suffer from heart failure than women of other races or ethnicities. This may be because African Americans are more likely to have high blood pressure, one of the main risk factors for heart failure. One study found that high blood pressure was the main cause of heart failure in 32% of African Americans, compared with 4% in whites.

Risk Factors You Can Change

There are other risk factors for heart failure that are completely or partly in your control, including certain conditions – such as high blood pressure, CAD, and diabetes – and lifestyle choices, such as smoking, not exercising, and not eating healthy. All of these can weaken or stiffen the heart and damage its pumping ability. Click on any of the conditions below to find out more about how they put you at risk for heart failure and what you can do about it.

High blood pressure

Coronary artery disease (CAD)

Diabetes

Obesity

Can heart failure be prevented?

Yes. The best way to prevent heart failure is to have a healthy lifestyle. Eat a healthy diet low in sodium and rich in fruits, vegetables, and whole grains. Exercise regularly, at least 30 minutes most days of the week. If you are overweight or obese, lose weight. If you smoke, stop. Don’t abuse alcohol and don’t use illegal drugs.

It is also critical to know your heart failure risk and control your risk factors, such as high blood pressure, coronary artery disease, diabetes, and obesity. If you are at risk for developing heart failure (AHA/ACC Stage A), you can take medications – in addition to the lifestyle changes mentioned above – to control your risk factors and reduce your risk of developing heart failure.

If you have had a heart attack but have no heart failure symptoms (AHA/ACC Stage B), you are at a considerably higher risk of developing heart failure. However, you can still reduce your risk of heart failure. Talk to your doctor about medications (beta-blockers, ACE inhibitors, or ARBs) or other treatments (implantable defibrillator if you have atrial fibrillation, angioplasty or stents if you have had a heard attack) that can help reduce your risk.

Types of Heart Failure

What are the different forms of heart failure?

Doctors usually classify heart failure based on which heart function or which side of the heart is most affected by the condition, regardless of the specific disease processes that may have caused it. Heart failure may involve problems with the chambers contracting to pump out blood (systolic heart failure) or problems with the chambers expanding to fill with blood (diastolic heart failure). It may affect only the right ventricle (right-sided heart failure) or the left (left-sided heart failure), or both.

Systolic & Diastolic Heart Failure

Every beat of the heart consists of two actions: contraction (systole) and relaxation (diastole). When the heart contracts, the lower chambers of the heart (ventricles) pump out blood into the lungs and the rest of the body. When the heart relaxes and expands, the ventricles fill completely with blood.

Adapted from The Merck Manual of Diagnosis and Therapy

Systolic heart failure is the result of a pumping problem (systolic dysfunction), caused by the ventricle losing its ability to contract normally because the heart muscle has become weak. When this happens, the heart can’t pump with enough force and not enough blood is pushed into the circulation.

Diastolic heart failure is the result of a filling problem (diastolic dysfunction), caused by the ventricle losing its ability to relax normally because the heart muscle has become stiff. When this happens, the heart can’t fill with enough blood, resulting in too little blood being pumped back out into the circulation. Diastolic heart failure is more common in women than men.

Most people with heart failure experience some degree of both blood-pumping and blood-filling problems. Doctors usually classify heart failure based on which problem is worse.

Left-sided and Right-sided Heart Failure

Heart failure can affect the left, right, or both sides of the heart. The heart is made up of four chambers. The left atrium and the right atrium on top mainly collect the blood, and the left ventricle and right ventricle on the bottom pump the blood. The right side of the heart receives oxygen-depleted or “used” blood from the body and pumps it to the lungs to be replenished with oxygen. The left side receives oxygen-rich blood from the lungs and pumps it to the rest of the body.

Left-sided heart failure is the most common type of heart failure.1 The left ventricle on the lower left side of the heart is the main pumping chamber. When it fails, oxygen-rich blood is not pumped to the rest of the body; instead, it can back up into the left atrium and into the lungs, where it builds up. Left-sided heart failure causes fatigue because the body is not receiving enough blood and shortness of breath because of the buildup of fluid (congestion) in the lungs.

Right-sided heart failure usually happens as a result of left-sided heart failure. As the failing left ventricle causes blood to build up in the lungs, the right ventricle finds it harder and harder to pump blood to the lungs to pick up oxygen. Less commonly, right-sided heart failure can also occur on its own, for example, when caused by lung disease (such as emphysema) or heart valve problems. Right-sided heart failure can cause blood to back up in the veins, resulting in swelling in the legs, ankles or belly, and can lead to shortness of breath when the belly is enlarged. Right-sided heart failure can also cause fatigue when the left ventricle doesn’t fill with enough blood and can’t supply the body with enough oxygen-rich blood.

For more information on heart anatomy and how the heart works, see The Heart & Circulation.

Heart Failure – Diagnosis & Treatment

How is heart failure diagnosed?

First, heart failure is diagnosed by ruling out other causes of your symptoms and documenting your heart’s ability to pump blood. Your doctor will do a thorough medical history and physical examination to look for signs and symptoms of heart failure. Your doctor will also order blood and imaging tests to rule out other possible causes for these symptoms and to check on your heart’s pumping capacity.

The medical history catalogs your symptoms, past illnesses, current health conditions, and medications. During the physical examination, the doctor will check your pulse, temperature, and blood pressure, as well as your abdomen, arms, and legs for any signs of swelling (fluid retention). He or she will also examine the veins in your neck, which can give a general idea of the amount of fluid in your body (like a fuel gauge). Using a stethoscope, the doctor will listen to your chest for abnormal sounds in your heart (such as a rapid heartbeat or heart murmurs indicating faulty heart valves) and in your lungs (such as the crackling sound of fluid buildup). A chest x-ray will be done to check the size of your heart and determine if there is fluid buildup in your lungs. An electrocardiogram will record the electric activity of your heart and check for irregular heartbeats.

If your doctor suspects that you have heart failure, he or she will order tests to check the movement of your heart and see if it is contracting and pumping normally. The most important of these tests is an echocardiogram, or “echo” for short. This test is used to see the size and movement of your heart and is the most used to measure your heart’s pumping ability, called ejection fraction (EF). Your ejection fraction is the percentage of blood pumped – or “ejected”- out of a filled pumping chamber (ventricle) during each heartbeat. It is usually measured on the left ventricle because the left ventricle is your heart’s main pumping chamber, supplying blood to the rest of the body.

Other imaging tests such as a nuclear ventriculogram and cardiac MRI may also be done. For more information, see our section on tests and diagnosis.

How is heart failure treated?

The goal of heart failure treatment is to relieve your symptoms, improve your quality of life, and slow the progression of heart failure. You will likely have to take medication for the rest of your life even if your heart failure resolves. Even with medications, your symptoms may reoccur, and additional treatment may be needed.

Heart failure is treated with a combination of lifestyles changes and medications. These therapies are designed not only to improve your symptoms and stop your heart failure from getting worse, but also to treat the underlying cause of your heart failure (such as heart disease, high blood pressure, or diabetes).

Lifestyle changes include:

Following a diet low in salt (like the DASH diet). Salt can cause extra fluid to build up in your body, making your heart failure worse.

Limiting the amount of fluids that you drink

Weighing yourself often and telling your doctor if you experience sudden weight gain. This could mean you have extra fluid building up in your body.

Exercising to help build up your fitness level and ability to be more active

Diuretics (water or fluid pills) to help reduce fluid buildup in your lungs and swelling in your feet and ankles

ACE inhibitors or Angiotensin Receptor Blockers (ARBs) to lower blood pressure, reduce the strain on your heart, and slow the progression of heart failure. These medications may also reduce the risk of a future heart attack.

Digoxin to help your heart pump blood more effectively (mostly for blood-pumping problems)

Hydralazine and isosorbide dinitrate to lower blood pressure and reduce the strain on your heart

In some cases of severe heart failure, lifestyle changes and medications may not be enough, and patients may need to be hospitalized or be given extra oxygen to help with breathing. Some heart failure patients are candidates for surgery or for implantable devices that help the heart pump properly, such as a mechanical heart pump. In rare cases of severe heart failure, the only option may be a heart transplant to replace the diseased heart with a healthy one.

African Americans often don’t respond as well to ACE inhibitors as whites do and may need adjustments made to the standard treatment. Although still receiving ACE inhibitor as part of their standard heart failure treatment, African Americans may need to also take diuretics to help control high blood pressure. Hydralazine and isosorbide dinitrate may also be added to their heart failure treatment to reduce the strain on the heart and improve survival.

For more information, see our overview articles on the treatment of systolic heart failure and treatment of diastolic heart failure.

Heart Failure – Prognosis

What is the prognosis for someone with heart failure?

Heart failure remains one of the most serious types of heart disease. The outlook for a woman with heart failure depends on her age, overall health, the severity of the condition, and how well she follows and responds to treatment.

Over the past 50 years, the overall chance of a woman dying of heart failure has dropped. The earlier the stage when your heart failure is diagnosed, the better your chance of surviving. Women in stage A of the AHA/ACC heart failure staging system can be treated to prevent or slow the progression of heart failure to a more advanced stage. A study of 2029 patients (52% were women) found that the heart failure stages were associated with worsening 5-year survival rates: from 97% in stage A and 96% in stage B to 75% in stage C and 20% in stage D. Survival is better for women with milder symptoms of heart failure. The milder your heart failure symptoms are, the more they can be eased with treatment and the better your prognosis will be. Women with NYHA class 1 heart failure symptoms do better than women with the more severe class 4 symptoms. A study of 3726 patients (25% were women) found that 66% of patients with NYHA classes 1 and 2 symptoms survived for at least 3 years, compared with 58% of patients with NYHA classes 3 and 4 symptoms.

Women with heart failure survive longer than men, perhaps because women tend to live longer than men. Some researchers think it is related to the cause of the heart failure. Women tend to have heart failure mostly due to high blood pressure, which develops gradually over a long period of time. Men are more likely to have heart failure as a result of coronary artery disease or heart attack, which can damage the heart muscle more severely and more quickly by depriving it of oxygen. When women develop heart failure caused by a heart attack or coronary artery disease, they do worse than women with heart failure due to other causes. Other researchers argue that women with heart failure have a better survival rate than men regardless of what caused the heart failure. The prognosis for someone with heart failure varies from person to person and is based on individual factors, such as the cause and severity of heart failure. There is much that you and your doctor can do to improve the quality of your life and your chances of survival, such as risk factor management, lifestyle modifications, and various forms of treatment.